Abstract
The purpose of this study was to explore the development of adolescent intelligence and cohort effects on their intelligence. Data for the study were drawn from the archival data of the secondary school attached to the University of Tokyo's Faculty of Education. Participants were 3,841 adolescents (1,920 females, M＝12.21 years, SD＝0.49; range 12–17), and the analyzed measure was the Tanaka B Intelligence Test - New Edition (Tanaka, 1953). Structural change, rank-order stability, and mean-level change of adolescents' intelligence were analyzed. The results showed that the structure of intelligence was highly consistent through adolescence and that rank-order stability was comparable to that found in previous research. As for mean-level change, adolescents' intelligence scores increased linearly and birth cohort had a statistically significant effect on the mean and slope of change. However, the directions of the effects were inconsistent. Later-born cohorts showed an increase of the mean and slope in the perception-related domain. On the other hand, these cohorts also showed a decline in their capacity to grasp the objects' relationships.
